The speed at which a program runs

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4
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81 views

Fixing terrible performance when watching/reading video and writing video files to disk

I have had this issue for quite some time and tried many times to fix it on my own and it always fails. IP schedulers, ionice and things like that always yield no result. I even went and bought an ...
3
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0answers
29 views

Is it bad to have thousands of autofs rules?

My company literally has thousands of NFS volumes, which we need to mount on a few of our servers. However, we never mount all of them at the same time; typically we mount about 12 at a time. Most of ...
3
votes
0answers
251 views

Very high I/O wait time on KVM virtual machine

Debian wheezy AMD64, 3 cores, 2560mb ram (virtual machine). 1 virtual drive on ext4, running on KVM. I decided to move it from raw to qcow2. Everything is ok and everything was going ok during ...
3
votes
0answers
147 views

How to generate graphs from lmbench results?

I need to use the lmbench benchmarking tool to get the system performance statistics. I am able to execute and run the results. In the results folder this is a MakeFile with this information # ...
3
votes
0answers
1k views

Send print job to printer immediately without queueing, aka increase print performance

I have a ruby/rails web application, one action of which sends PDF files that have been generated by the app to a Xerox 4127 printer on the network. This is accomplished via shelling out and running ...
2
votes
0answers
31 views

Benchmarking under SELinux Sandbox with Phoronix Test Suite

I would like to run the Phoronix Test Suite 6.2.2 under the SELinux sandbox on Fedora 23, but I can't execute it using $ sandbox ./phoronix-test-suite. I probably don't have the correct SELinux type. ...
2
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0answers
76 views

ZFS (on linux) performance issues

I have a server setup with RaidZ2 (8 disks in array) + 2 spares (+ system disk). The disks are 6TB each, 7200 RPM SAS The machine runs Centos7 x86_64 (not a VM), and has 128 GB of RAM and 48 cores ...
2
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0answers
45 views

Is “top” accounting for Kernel Interrupts?

I have a simple interrupt that is triggered by a GPIO-input. The IRQ only increments a variable and returns. When I turn the frequency of the interrupts up to somewhere around 10-20 kHz, the system ...
2
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801 views

Linux Mint 17.1 Cinnamon is slower in computer than in Virtual Box

After some months working in a VirtualBox VM with Linux Mint (the host as a Windows 7), I've finally installed Mint 17.1 Cinnamon on the same computer. And the experience hasn't been good. The fact ...
2
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91 views

How to use blktrace to monitor the eMMC Flash access pattern?

I'm trying to simulate a FTL(Flash Translation Layer) algorithm and evaluate its performance. What I need is a trace file of a flash access(containing information about block and page access). I'm ...
2
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0answers
72 views

JVM low-memory tuning

What command-line options would provide the lowest memory-footprint JVM, in OpenJDK, or possibly other JVMs (Linux/Debian)? I'm willing to disable JIT, live with slow or choppy garbage collection, ...
2
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0answers
62 views

Why does my fresh Debian have a high latency?

The time between clicking and seeing a response is very high. Typing looks very funny, and makes me feel queasy. I think there's about 50-20ms "extra". I would expect a top notch linux distro to have ...
2
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0answers
68 views

What tools can show me the CPU usage that doesn't appear in top/sar?

I have a virtual machine that's using ip_tables to set up some connection forwarding. According to top, sar and /proc/stat, I'm > 99% idle. However, perf says I'm only about 72% idle, with the rest ...
2
votes
0answers
113 views

Cgroups - memory subsystem

I want to set the memory.limit_in_bytes parameter for a control group and disable OOM, so processes freeze when the limit is reached. But i want to change that limit dynamically, if there is more ...
2
votes
0answers
582 views

Local disc copy at 10MB/s! What could be the problem?

I am running a Debian 6.0.6 (before you ask). I have a regular desktop computer, nothing fancy... but when I copy a file using nautilus I am getting 10MB/s copy speed and the system is completely ...
2
votes
0answers
528 views

Why if I don't disable nm-applet and xfce4-volumed my startup slows down?

I'm running Xubuntu 12.04, and after I ran the update, my login started slowing down big time. I've dabbled a little bit with the programs in Settings -> Settings Manager -> Session and Startup, and ...
2
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0answers
873 views

“Remote function call interrupts” (CAL in /proc interrupts). What is it?

I'm running a test program which generates a large number of threads and asynchronous I/O. I'm seeing very high counts of these interrupts in /proc/interrupts, the program cannot scale beyond a ...
2
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0answers
297 views

Connected external HDD slows down system

I need to connect large external hard disks (with many many files) to a system running Ubuntu. I have no idea how the Linux kernel is treating the inodes for the external drives, but attaching huge ...
2
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0answers
317 views

Perform test of aes-ni and aes module in linux kernel

Since both aes-ni and aes module are available in linux kernel , how can I give it a performance test , to decide which one's faster ?
2
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0answers
490 views

Software raid checksumming slow

On my new 24 disk array I get 900 MB/s of raw read or write using dd to all the disks. When I set the disks up as a 24 disk RAID6 I get 400 MB/s write and 600 MB/s read. It seems to be due to ...
1
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0answers
52 views

Why my server cannot serve more than 400 concurrent connections

I have an Ubuntu 14.04 LTS, kernel 3.13 in a Intel Xeon + 8Gb box. It has apache 2.4.7 configured in mpm worker with up to 4000 workers. The max bandwidth allowed by the ISP is 100Mbps. If I test ...
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0answers
27 views

Configure xterm to use ctrl+shift+c/ctrl+shift+v for copy/paste?

I was using terminator for my terminal emulator, but I'm seeing huge performance issues with it. ie, launching a new terminal session takes 20-30 seconds on my netbook. gnome-terminal is better, but ...
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0answers
182 views

RHEL 7 Still CPU Frequency Scaling

When machine is imaged with: RHEL6.x CPU speeds report full 3.3Ghz speed for all CPUs cpupowerutils is not installed RHEL7.x CPU speeds vary (shown in example below) cpupowerutils is installed ...
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126 views

Reducing Number of MariaDB/MySQL Threads

So I'm running a MariaDB 10 database on a single core server; not super powerful, but then my needs aren't huge either. However, one thing I've noticed is that if I look in htop I have around 28 ...
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0answers
18 views

What can interrupt execution of threads which are pinned to cores?

I do low-latency application development and I use isocpu and set thread affinity to reduce (eliminate?) context switching during my critical threads. However, I am unsure what other types of ...
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0answers
121 views

Debugging Slow Queries in MariaDB/MySQL

I've set up a MariaDB server and everything is running well, with most queries executing in well under 20 milliseconds, but every so often a query will take half a second or longer (sometimes several ...
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0answers
58 views

Why does flood ping to localhost result in lower RTT's?

I used ping to do an estimate of lower bound for HTTP request times as part of a feasibility study. In order to make the test faster I lowered the interval of the ping (to get enough pings to get a ...
1
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0answers
160 views

How does performance measurement tool 'perf' actually work?

perf is a tool which accesses the performance counter registers of an machine and gives out metrics to user to analyze the system performance. What I am curious about is, when I read the parts of ...
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0answers
47 views

How can I profile/benchmark RAM performance?

I would like to know if my memory hardware is a bottleneck of my system performance. I am dealing with really old hardware (late 2000). If there is room for improvement, I would like to upgrade. ...
1
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0answers
144 views

Disk configuration options, what can affect performance

I have 2 disks, the same model and vendor, first one , probably performs faster. We do write into multiple files. Can you compare 2 configurations and tell what can affect performance? 1. (faster) ...
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0answers
33 views

Is the perfmon2 tool obsolete due to the same functionality being included in the current Linux kernel?

I was having some issues with the PAPI tool and multiplex and this answer by the PAPI creator led me to check out perfmon2: http://lists.eecs.utk.edu/pipermail/ptools-perfapi/2008-April/000900.html ...
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193 views

'nc' using ~100% CPU when transferring a FIFO file

On the server which is always connected I’m using this in a crontab: @reboot nc -k -l 1337 < /tmp/fifo.fifo On the client which is not always on the network or switched on I’m using this ...
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0answers
133 views

Variations in Ubuntu 12.04 /usr/bin/time statistics

I have a command line tool which I run on Ubuntu 12.04.5 LTS. I need to calculate the cpu time for this program. I have been checking /usr/bin/time function. command: /usr/bin/time -v -a -o ...
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0answers
188 views

How to diagnose CPU performance problems?

Recently I bought a new netbook based on AMD A4-1200 CPU and installed Linux Mint 17 with XFCE. RAM is 4GB So, testing some of my programs, I found very strange behavior. On random intervals, the ...
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176 views

Properly mount a windows share to move files on the mountpoint

This question resulted from a question of mine on stackexchange. I mount a windows share with mount -t cifs -o ...
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0answers
60 views

How fast is a process reading/writing virtual memory?

We have top, htop, iotop, iostat, vmstat, etc, to measure many different things on Linux, but how can one measure how much MB/s a process is reading and writing to/from RAM, i.e., virtual memory?
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37 views

How can we measure performance overhead resulting from writing to files or folders?

I have a tool which takes as input a folder or a file and then it logs operations done on that file or folder (modifying,deletion,creating new folders or files, etc). I was looking for a way to ...
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0answers
547 views

Horrible Iceweasel and Opera performance when watching youtube

I have 64-bit Debian on laptop with Intel Core 2 Duo T9300 2.5GHz, Nvidia Quadro NVS140M GPU and 4GB RAM. For now - im on vacation and im using 3G USB modem. I have relatively slow but high quality ...
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0answers
112 views

Ubuntu with LAMP+Mediawiki suffering spikes

I'm sorry if this question is off topic, but I'll give it a shot: I have a VPS running Ubuntu 12.04, a LAMP stack, and Mediawiki. After installing Mediawiki I noticed that my wiki site was spiking, ...
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0answers
221 views

Do kernel threads seem to interfere with full tickless mode?

I'm trying to disable local timer interrupts for low latency. I have full tickless mode enabled in the kernel config and I have the boot parameter nohz_full set for the cores in question. However ...
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0answers
454 views

Monitoring Disk Latency

We have quite a few physical machines in our environment, yet we have no trending data over a period of time for disk latency statistics. We can easily run the standard iostat commands to see what the ...
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0answers
32 views

Amount of memory transfer on a running Linux

Can I determinate the amount of RAM exchange (between the CPU and the RAM) on a running Linux system? I'm not looking for the max RAM speed (then memtest would be valid answer). I'm looking for the ...
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0answers
54 views

memory consumption alert

My VPS has reported a memory consumption alert says reached 273% and I cannot access any of my sites. But I checked on the terminal today and it does not look like a memory problem. Am I correct in ...
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0answers
326 views

Why does my CMS run extremely slow in my workstation (Ubuntu)

For over a year I have been struggling with the response speed on my Drupal v7.2x CMS install. Let me explain. I'm running Drupal 7.2x on an Ubuntu 12.10 (upgrade to 13.xx pending) for the purpose of ...
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0answers
373 views

X high CPU when using Java applications

Only recently, my Freemind program has become extremely sluggish and unresponsive (big lag) when moving my mind map around. I use Arch Linux with xfce4. Freemind is made with Java. If I move the mind ...
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11 views

Why kernel may be throttled?

My MBR start freezing up for over hour and I've found that my kernel reported being throttled, e.g. (this is just a sample for 2 seconds) $ sudo fs_usage | | grep -i throttled 12:26:45 THROTTLED ...
0
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0answers
29 views

Slow USB 3 write speed

Writing to my USB 3 thumb drive (SanDisk Extreme SDCZ80-064G-FFP) is very slow on Linux: 1 GB takes longer than 200s. Using Windows (dual-boot on the same computer), the same 1 GB file can be copied ...
0
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0answers
11 views

Performance problem Fedora 23 32-bit @ Dell D630 4GB/Nvidia

I have installed Fedora 23 32-bit at Dell D630 4GB with NVidia Quattro NVS 135M (nvidia.ko, not nouveau.ko). And I have permanent performance problem as X-Windows (Gnome) are very slow and laggy. I ...
0
votes
0answers
10 views

Improving MPI performances on a heterogeneous cluster

I am running some parallel programs on a heterogeneous cluster: 2 CentOS virtual nodes (node 1 & node 2) on a Mac host and 2 others (node 3 & node 4) on a PC. When I run a parallel program ...
0
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0answers
22 views

Ubuntu trusty format disk slower than RHEL7?

I observed that disk formatting is much slower in Ubuntu than in RHEL7. Does anybody know why that is? EDIT: Forgot to mention, I'm formatting the disk with ext4. Using mke2fs